In their experiments, the researchers gave the snails two forms of training: strong and weak. During strong training, they first sprayed the snails with banana-flavored water, which the snails treated as neutral in its appeal: They would swallow some but then spit some of it out. Then the team gave the snails sugar, which they gobbled up avidly.<\/p>\n

When they tested the snails as much as a day later, the snails showed that they had learned to associate the banana flavor with the sugar from that single experience. The snails seemed to perceive the flavor as more desirable: They were much more willing to swallow the water.<\/p>\n

In contrast, the snails did not learn this positive association from a weak training session, in which a bath flavored with coconut was followed by a much more diluted sugar treat. The snails continued to both swallow and spit out the water.<\/p>\n

So far, the experiment was essentially a snail version of Pavlov\u2019s famous conditioning experiments in which dogs learned to drool when they heard the sound of a bell. But then the scientists looked at what happened when they gave the snails a strong training with banana flavoring followed hours later by a weak training with coconut flavoring. Suddenly the snails learned from the weak training, too.<\/p>\n

When the researchers switched the order and did the weak training first, it again failed to impart a memory. The snails still formed a memory of the strong training, but that didn\u2019t have a retroactive strengthening effect on the earlier experience. Swapping the flavors used in the strong and weak trainings also had no effect.<\/p>\n

The scientists concluded that the strong training pushed the snails into a \u201clearning-rich\u201d period in which the threshold for memory formation was lower, enabling them to learn things they otherwise would not have (such as the weak-training association between a flavor and dilute sugar). Such a mechanism could help the brain direct resources toward learning at opportune times. Food could make the snails more alert to potential food sources nearby; brushes with danger could sharpen their sensitivity to threats.<\/p>\n<\/div>\n

<\/br><\/br><\/br><\/p>\n